Identification of the Pathogens Causing Cunninghamia lanceolata Copper Blight in Fujian Province and Screening of Fungicides

To identify the copper blight pathogen of Chinese fir in Fujian Province and identify efficient fungicides, we collected samples of copper blight from four regions in eastern, southern, western and northern Fujian.The samples were then isolated, and the pathogenic strains were identified based on morphological characteristics and molecular biology techniques.Additionally, the inhibitory effects of carbendazim, tebuconazole, and flusilazole on the red rot pathogen were assessed using the mycelial growth rate method.And the inhibitory effects of three commonly used fungicides on copper blight pathogen were determined using the mycelial growth rate method.The results showed that four species of Pestalotiopsis were collected, including Pestalotiopsis microspora,Pestalotiopsis theae,Pestalotiopsis cocculi and Pestalotiopsis oxyanthi.Among them, P.microspora and P.theae were highly pathogenic and had the widest distribution areas.Toxicity tests of fungicides indicated that carbendazim was the most effective in inhibiting the mycelial growth of Pestalotiopsis species, followed by difenoconazole and iprodione, with EC₅₀ values of 0.19 μg·mL^-1,10.42 μg·mL^-1 and 20.99 μg·mL^-1.The study showed that P.microspora and P.theae were the primary pathogens responsible for copper blight in Fujian area, and that carbendazim might have a better application prospect in the control of copper blight.